Sensor system and method

ABSTRACT

A system includes a structure bonding layer and a sensor. The structure bonding layer is disposed on a structure. The structure bonding layer is a metallic alloy. The sensor includes a non-metallic wafer and a sensor bonding layer disposed on a surface of the non-metallic wafer. The sensor bonding layer is a metallic alloy. The sensor bonding layer is coupled to the structure bonding layer via a metallic joint, and the sensor is configured to sense data of the structure through the metallic joint, the structure bonding layer, and the sensor bonding layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/616,105, filed 7 Jun. 2017, which is incorporated byreference herein.

FIELD

The subject matter described herein relates to sensors.

BACKGROUND

Sensors may be used in a variety of applications. For example, inelectro-mechanical systems, surface acoustic wave (SAW) devices may beused as sensors to measure torque, temperature, pressure, and otherparameters. The SAW devices may be wafer level hermetically capped orplaced and sealed inside of hermetic discrete packages, and then mountedonto structures in order to sense data of the structure. The SAW devicesmay be mounted onto structures such as shafts, rods, blades, oralternative structures used in various applications such as aviation,oil and gas, transportation, renewable energy extraction, or the like.

The processes of mounting sensors to structures presently includeseveral issues. One issue present with mounting sensors to certainstructures is that many structures are too large to fit intoconventional ovens or reflow equipment or may not be able to betransported to a location having conventional ovens or reflow equipmentto mount the sensors to the structure. Therefore, many SAW devices aremounted to structures using an adhesive or epoxy material. However,using an epoxy or adhesive to mount a sensor to a structure limits theoperating temperature of the system, reduces the sensitivity of thesensor to sense data of the structure, limits the capability of futurere-workability of the sensors mounted to the structures, and requiressignificant time for the epoxy or adhesive to properly cure, whichincreases associated manufacturing and material costs. It isadvantageous to have a more robust mounting method to attach thesesensors both in the field and in a production setting.

BRIEF DESCRIPTION

In one embodiment, a system includes a structure bonding layer and asensor. The structure bonding layer is disposed on a structure. Thestructure bonding layer is a metallic alloy. The sensor includes anon-metallic wafer and a sensor bonding layer disposed on a surface ofthe non-metallic wafer. The sensor bonding layer is a metallic alloy.The sensor bonding layer is coupled to the structure bonding layer via ametallic joint, and the sensor is configured to sense data of thestructure through the metallic joint, the structure bonding layer, andthe sensor bonding layer.

In one embodiment, a method includes disposing a structure bonding layeron a structure. The structure bonding layer is a metallic alloy. Themethod includes disposing a sensor bonding layer on a surface of anon-metallic wafer of a sensor. The sensor bonding layer is a metallicalloy. The method also includes coupling the structure bonding layer tothe sensor bonding layer via a metallic joint. The sensor is configuredto sense data of the structure through the metallic joint, the structurebonding layer, and the sensor bonding layer.

In one embodiment, a system includes a sensor, an inlay, and a structurebonding layer. The sensor includes a sensor bonding layer disposed on asurface of the sensor. The sensor bonding layer is a metallic alloy. Theinlay is disposed on a curved surface of a structure. The inlay includesa planar outer surface. The structure bonding layer is disposed on theplanar outer surface of the inlay. The structure bonding layer is ametallic alloy. The sensor bonding layer is coupled to the structurebonding layer via a metallic joint, and the sensor is configured tosense data of the structure through the metallic joint, the structurebonding layer, and the sensor bonding layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive subject matter will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 illustrates a cross-sectional view of a system in accordance withone embodiment;

FIG. 2 illustrates a partial cross-sectional view of the system of FIG.1 in accordance with one embodiment;

FIG. 3 illustrates a method flowchart in accordance with one embodiment;

FIG. 4 illustrates a cross-sectional view of a system in accordance withone embodiment;

FIG. 5 illustrates a cross-sectional view of a system in accordance withone embodiment;

FIG. 6 illustrates a perspective view of the system in accordance withanother embodiment of the present disclosure; and

FIG. 7 is an enlarged cross-sectional view of the system shown in FIG.6.

DETAILED DESCRIPTION

One or more embodiments of the inventive subject matter described hereinprovide systems and methods having a sensor that is disposed on astructure via a metallic sensor bonding layer and a metallic structurebonding layer joined to a metallic joint in order to sense data of thestructure through the metallic joint, the sensor bonding layer, and thestructure bonding layer. The structure may be a large structure such asa rod, a shaft, a blade, or the like, used in applications such asaviation, oil and gas, transportation, renewable energy extraction,power and energy systems, or the like. The sensor may sense temperaturedata, strain data, stress data, and/or the like of the structure. Forexample, the sensor may sense temperature data of a conduit thattransfers oil, may sense the temperature of the oil that is transferredinside of the conduit, may sense the strain of a rotating shaft, or thelike. The systems and methods described herein may improve sensorsensitivity, enable exposure of systems to higher operatingtemperatures, and reduce an amount of creep of the bonding materialsrelative to systems that do not have a metallic bond.

FIG. 1 illustrates a cross-sectional view of a system 100 in accordancewith one embodiment. The system 100 includes a sensor 104 that iscoupled to a structure 102. The structure 102 may be a shaft, a plate, ablade, a rod, or the like. The structure 102 may be a manufactured outof a metallic and/or non-metallic material. For example, the structure102 may be a shaft used to transfer oil or gas, may be a rotor blade ofa wind turbine, may be a rotating or stationary shaft of an aerialdevice, or the like. Optionally, the structure 102 may be anyalternative component used in applications such as aviation, oil andgas, transportation, renewable energy extraction, power and energysystems, or the like.

The sensor 104 has a first component 110 that is bonded to a secondcomponent 112. The first and second components 110, 112 of the sensor104 may be single crystal quartz wafers that are coupled together by aliquid crystal polymer (LCP) material. Optionally, the sensor 104 mayhave more than two or less than two components. Optionally, thecomponents of the sensor 104 may be held together by any alternativematerial. The sensor 104 is used to sense data. For example, the sensor104 may be a SAW device that includes a strain gauge, torque sensor,temperature sensor, and/or the like, that is used to sense temperaturedata, strain data, stress data, and/or the like of the structure 102.Optionally, the sensor 104 may be an alternative sensor that senses(e.g., records, collects, reads, measures, or the like) informationabout the structure 102.

The sensor 104 is coupled to a first side 114 of a metallic joint 106 ofthe system 100. Additionally, the structure 102 is coupled to anopposite, second side 116 of the metallic joint 106. The sensor 104 isoperably coupled to the structure 102 via the metallic joint 106 inorder to sense data of the structure. In the illustrated embodiment ofFIG. 1, a surface of the sensor 104 that is coupled to the first side114 of the metallic joint 106 and a surface of the structure 102 that iscoupled to the second side 116 of the metallic joint 106 are planar orsubstantially planar surfaces (within manufacturing tolerances).Optionally, one or more of the sensor 104 or the structure 102 may havenon-planar surfaces that are coupled to the metallic joint 106. Forexample, the structure 102 may be a shaft that has a cross-sectionalshape that is generally circular and the sensor 104 is operably coupledto the circular cross-sectional shape of the outer surface of the shaftstructure 102. Optionally, the structure 102 may be a blade with acurved outer surface and the sensor 104 is operably coupled to thecurved outer surface of the blade structure 102.

In one embodiment, the system 100 includes a structure 102 havingmultiple sensors 104 that are operably coupled with the structure 102via a metallic joint 106. For example, the multiple sensors 104 may bearranged as an array of multiple sensors 104 in columns and rows or maybe randomly arranged and coupled with one or more surfaces of thestructure 102. Optionally, the system 100 may have one or more metallicjoints 106 that couple the sensors 104 with the structure 102. Forexample, a single metallic joint 106 may couple multiple sensors 104with the structure 102, multiple metallic joints 106 may couple themultiple sensors 104 with the structure 102, or the like.

FIG. 2 illustrates a partial cross-sectional view A of the system 100 ofFIG. 1 including the sensor 104 that is made of a quartz/non-metallicmaterial in accordance with one embodiment. The sensor 104 has a sensorbonding layer 204 that is disposed on a surface 212 of the sensor 104.The sensor bonding layer 204 is a metallic alloy that can be coupled tothe metallic joint 106. The sensor bonding layer 204 is a solderableand/or braze-able finish. The layer 204 can be deposited by sputtering,plating, or other application techniques. For example, the sensorbonding layer 204 may represent or include titanium, copper, silver,tin, nickel, gold, electroless nickel immersion gold (eNIG), and/or thelike, that is disposed on the surface 212 of the sensor 104. In anon-limiting example, the sensor bonding layer 204 is a stack defined byindividual layers of titanium, nickel, and gold. For example, thethicknesses of the layers may be about 1.2 micrometers nickel, about1500 A gold, and about 1000 A titanium. The modifier “about” indicatesthat the values are inclusive of other values above and below theindicated values within a threshold range, such as ±1%, 2%, 3%, or thelike of the indicated values. Alternatively, the sensor bonding layer204 may be a different metallic compound and/or metal alloy that may bebonded to the metallic joint 106 and that provides adhesion between thesensor 104 and the structure 102. The sensor bonding layer 204 may havea higher operating temperature and a higher modulus of elasticityrelative to an epoxy, adhesive, liquid crystal polymer, or the like. Inan alternative embodiment, the sensor 104 may be manufactured of ametallic material that is coupled directly to the metallic joint 106such that the system 100 is devoid of the sensor bonding layer 204.

The structure 102 has a structure bonding layer 202 that is disposed ona surface 214 of the structure 102. In one embodiment, the surface 214may be an outer, or exterior surface of the structure 102 that ismetallic and allows for metallic bonding between the structure and themetallic joint 106. Optionally, the surface 214 may be an interiorsurface of a structure 102. For example, the sensor 104 may be bonded tothe interior of the structure 102 (e.g., the interior of a hollow shaft,or the like) and the structure bonding layer 202 may be disposed on aninterior surface 214 of the structure 102.

The structure bonding layer 202 is a metallic compound and/or metallicalloy that can be coupled (e.g., bonded) to the metallic joint 106. Thestructure bonding layer 202 is a layer of a material suitable formetallic bonding that is disposed on the surface 214 of the structure102. In one or more embodiments, the structure bonding layer 202 may bea local metallization of the surface 214 of the structure 102. In anon-limiting example, the structure bonding layer 202 may be an inlay,such as a copper inlay, along the surface 214 of the structure 102, asdescribed below with reference to FIG. 6. The structure 102 may or maynot be manufactured out of a material that is directly solderable to thesecond side 116 of the metallic joint 106. For example, the structure102 may be manufactured out of a steel alloy that is solderable to themetallic joint 106 or may be manufacturing out of brass or anothernon-steel alloys that is not solderable to the metallic joint 106. Thestructure bonding layer 202 may be a metallic alloy that has a higheroperating temperature and a higher modulus of elasticity relative to anepoxy, adhesive, liquid crystal polymer, or the like. In a non-limitingexample, the structure bonding layer 202 may be electroless nickelimmersion gold (eNIG), electrolytic nickel gold (NiAu), or the like,when there cannot be a direct metallic bond between a non-metallicstructure 102 and the sensor 104, or when the structure 102 and/or thesensor 104 are made of materials that are not applicable for metallicbonding and/or wetting.

The metallic joint 106 is a metallic bond that operably couples thesensor 104 with the structure 102. Non-limiting examples of the materialof the metallic joint 106 include solder alloys composed of tin, silver,copper, gold, lead, germanium, and/or indium. Some non-limiting examples(by percent weight) of specific compositions include 96.5% tin-3%silver-0.5% copper; 80% gold-20% tin; 92.5% lead-5% tin-2.5% silver; 88%gold-12% germanium; or 82% gold-18% indium. Active solders withtitanium, magnesium, and/or rare earth elements may be used as themetallic joint 106. Alternatively, the metallic joint 106 may includedifferent materials and/or alloys, such as transient liquid phasesintering, sintered silver, sintered copper, sintered nickel, brazealloys, and/or the like.

The conditions in the field, such as temperature, humidity, pressure,and the like, may vary and may deviate from preferred conditions forbonding. Conventional electronic soldering operations may utilizenon-metal flux chemicals that are mixed into the solder alloy, and theresulting solder mixture is heated with specific ramp rates to match thechemical flux activation/oxide removal reaction. In very largeassemblies the process window may be too long for conventional fluxes towork (e.g., the fluxes may dry out during an exceedingly long ramp totemperature). In one or more embodiments, the active elements in themetallic joint 106 can aid in solder joint formation, replacing or atleast supporting the conventional non-metal flux chemicals.

The sensor bonding layer 204 is coupled to the first side 114 of themetallic joint 106, and the structure bonding layer 202 is coupled tothe second side 116 of the metallic joint 106 in order to operablycouple the sensor 104 with the structure 102. The sensor 104 senses dataof the structure 102 through the metallic joint 106, the sensor bondinglayer 204 and the structure bonding layer 202. The sensor 104 may sensetemperature, strain, stress, pressure, or the like, of the structure102. For example, a torque may be applied to the structure 102. Thesensor 104 may measure the stress or strain on the structure 102 that istransferred through the structure bonding layer 202, the metallic joint106, and the sensor bonding layer 204 to the sensor 104.

In one embodiment, the modulus of elasticity of the material of thesensor bonding layer 204 and the modulus of elasticity of the materialof the structure bonding layer 202 impacts the amount of strain datathat is transferred from the structure 102 through the structure bondinglayer 202, the metallic joint 106, and the sensor bonding layer 204 tothe sensor 104. For example, as the modulus of elasticity of thematerial of the sensor and structure bonding layers 204, 202 increases(e.g., the materials become stiffer), the accuracy of the sensor 104measuring strain data of the structure increases. Alternatively, as themodulus of elasticity of the material of the sensor and structurebonding layers 204, 202 decreases (e.g., the materials become lessstiff), the accuracy of the sensor 104 measuring strain data of thestructure decreases. For example, the sensor 104 that is operablycoupled with the structure 102 via the metallic joint 106 is moreaccurate relative to the sensor 104 that is operably coupled with thestructure 102 via an adhesive and/or epoxy material. Additionally, thesensor 104 that is operably coupled with the structure 102 via themetallic joint 106 may be used in systems having higher operatingtemperatures relative to the sensor 104 that is operably coupled withthe structure 102 via an adhesive and/or epoxy material. Additionally,the sensor 104 that is operably coupled with the structure 102 via themetallic joint 106 may have less creep of the metallic joint than thesensor 104 that is operably coupled with the structure 102 via anadhesive and/or epoxy. To achieve acceptable strain transfer from thestructure 102 to the sensor 104, the modulus of elasticity in thebonding layers 204, 202 may have a minimum value of 700 MPa. In order toincrease accuracy of the strain data that is transferred to the sensor104, it is advantageous to have a modulus of elasticity above 2000 MPa.Additionally, the modulus of elasticity at varying temperatures mayimpact the accuracy of the strain data that is transferred to the sensor104. Non-limiting examples of metals, metal alloys, and/or metallicmaterials disclosed have sufficient modulus of elasticity at hightemperatures. For example, in conventional epoxy materials, the modulusdecreases at temperatures greater than 150° C. Alternatively, metalsand/or metal alloys can be used between 40% to 75% of the homologoustemperature with minimal creep. In the alloys listed, the homologoustemperature may have a temperature greater than 1000° C.

FIG. 3 illustrates a method flowchart 300 of the system 100 inaccordance with one embodiment. At 302, a structure bonding layer 202 isdisposed on a surface 214 of a structure 102. For example, the structurebonding layer 202 may be a local metallization of the surface 214 of thestructure 102, or the structure bonding layer 202 may be a layer of asolderable material that is disposed on the surface 214 of the structure102. The structure bonding layer 202 may have a surface area on thesurface 214 of the structure 102 that is substantially equivalent to asurface area of the surface 212 of the sensor 104. Optionally, thestructure bonding layer 202 may have a surface area that is greater thanor less than the surface area of the surface 212 of the sensor 104.Optionally, the structure bonding layer 202 may have a surface area thatis substantially the same as the surface area of the metallic joint 106,may have a surface area that is less than the surface area of themetallic joint 106, or may have a surface area that is greater than thesurface area of the metallic joint 106.

At 304, a sensor bonding layer 204 is disposed on a surface 212 of asensor 104. For example, the sensor bonding layer 204 may be a layer ofa metallic material. The structure bonding layer 202 and the sensorbonding layer 204 may be common or unique metallic alloys. The sensorbonding layer 204 may have a surface area that is substantiallyequivalent to a surface area of the surface 212 of the sensor 104, mayhave a surface area that is less than the surface area of the surface212, or may have a surface area that is greater than the surface area ofthe surface 212. Optionally, the sensor bonding layer 204 may extend anarea that is substantially equivalent to, is less then, or is greaterthan the surface area of the metallic joint 106.

In one or more embodiments, the sensor bonding layer 204 and/or thestructure bonding layer 202 use self-orientation or self-alignment toassemble the sensor 104 to the structure 102 via the metallic joint 106.The metallic joint 106 may be a solder layer made of a solder alloyhaving wetting properties that enables the sensor bonding layer 204 ofthe sensor 104 to self-align with the structure bonding layer 202 of thestructure 102 when the sensor 104 is bonded to the structure 102. Forexample, the metallic joint 106 allows the sensor 104 to self-align withthe structure 102 without the use of additional pick-and-placeequipment, additional fixture equipment, or the like.

At 306, the structure bonding layer 202 is coupled to the sensor bondinglayer 204 via the metallic joint 106. For example, the sensor bondinglayer 204 is coupled with a first side 114 of the metallic joint 106,and the structure bonding layer 202 is coupled with an opposite, secondside 116 of the metallic joint 106.

The sensor 104 is operably coupled with the structure 102 via themetallic joint 106 at a location outside of a conventional reflow oven.For example, the structure 102 may be part of an assembly that may notbe able to be transferred to a reflow oven, the structure 102 may not beable to be disassembled from the assembly to be transferred to a reflowoven, the structure 102 may not be able to fit inside of a reflow oven,the structure 102 may be manufacture out of a material that cannotwithstand conventional operating temperatures of a conventional reflowoven, or the like.

In one embodiment illustrated in FIG. 4, the sensor 104 is operablycoupled with the structure 102 via the metallic joint 106 by aninduction coil 402 that applies electrical stimuli to the metallic joint106. For example, the sensor 104 may be held in a position (e.g., by afixture, by an operator, or the like) and the induction coil 402 may beplaced in contact with, close by to, around, or the like, the sensor 104and the substrate 102 to which the sensor 104 is to be bonded. In oneembodiment, the induction coil 402 may be wrapped around the system 100,as illustrated in FIG. 4. Additionally or alternatively, the inductioncoil 402 may be wrapped around the sensor 104 such that the inductioncoil 402 is substantially parallel to the substrate 102. Additionally oralternatively, the induction coil 402 may be placed in contact with thesystem 100 by an alternative configuration. The induction coil 402applies localized electrical stimuli to the metallic joint 106 toactivate reflow the metallic joint 106 in order to operably couple thesensor 104 with the structure 102. In other embodiments differenttechniques can be utilized to activate the reflow of the metallic joint106 for coupling the sensor 104 with the structure 102, such asmicrowave and/or laser-assisted solder reflow.

In one embodiment illustrated in FIG. 5, the sensor 104 is operablycoupled with the structure 102 via the metallic joint 106 by an activereflow process at the metallic joint 106. For example, an exothermicmetallic film such as a Reactive Nano Technologies (RNT) film 502, or analternative material, may be placed within the metallic joint 106 inorder to locally reflow the metallic joint 106. The sensor 104 may beheld in a position (e.g., by a fixture, by an operator, or the like).Electrical stimuli that is applied to the film 502 by a fixture, anelectrical source, or the like, activates reflow of the metallic joint106 in order to operably couple the sensor 104 with the structure 102.

Returning to FIG. 3, at 308, the sensor 104 senses data of the structure102 through the structure bonding layer 202, the metallic joint 106, andthe sensor bonding layer 204. For example, the sensor 104 may sense(e.g., collect, read, measure, obtain, or the like) data of thestructure 102. The sensed data of the structure 102 transfers from thestructure 102, through the metallic joint 106, through the metallicstructure bonding layer and sensor bonding layer, to the sensor 104. Forexample, as the modulus of elasticity of the metallic sensor bondinglayer 204 and the structure bonding layer 202 increases, the transfer ofthe sensed strain data of the structure 102 improves relative to anon-metallic sensor bonding layer 204 and non-metallic structure bondinglayer 202. The data of the structure 102 may include temperature,pressure, stress, strain, or the like. Optionally, the data of thestructure 102 may include sensed data of a fluid that is being containedinside of the structure 102. Optionally, the data of the structure 102may include sensed data of an externality characteristic to which thestructure 102 is exposed (e.g., environmental ambient temperature,ambient pressure, ambient humidity, or the like). Optionally, the senseddata of the structure 102 may include any alternative data that issensed (e.g., collected, measured, read, obtained, or the like) by thesensor 104.

FIG. 6 illustrates a perspective view of the system 100 according toanother embodiment of the present disclosure. In the illustratedembodiment, the sensor 104 is coupled to the structure 102 via an inlay602 on the structure 102. The inlay 602 has an outer surface 604 that isplanar. The outer surface 604 is a top surface in the illustratedorientation. The sensor 104 is coupled or mounted to the planar outersurface 604. Optionally, the surface 606 of the structure 102surrounding the inlay 602 is curved (e.g., not planar). For example, thestructure 102 can be a cylindrical shaft, and the surface 606 representsthe curved outer surface of the shaft. In another example, the structure102 can be a rotor blade, and the surface 606 represents a curved outersurface of the rotor blade. The planar outer surface 604 of the inlay602 may provide a better surface for adhesion of the sensor 104 to thestructure 102 than the curved surface 606 of the structure 102.

In the illustrated embodiment, the inlay 602 projects beyond the curvedsurface 606 of the structure 102. The planar outer surface 604 of theinlay 602 is offset from the curved surface 606 surrounding the inlay602. The inlay 602 includes side walls 608 that each project from thecurved surface 606 of the structure 102 to the planar outer surface 604of the inlay 602. The inlay 602 in the illustrated embodiment representsa pedestal or platform.

Although the structure 102 is curved in the illustrated embodiment, thesurface 606 of the structure 102 may be flat and planar in anotherembodiment. For example, the structure 102 can be a planar bar, beam,and/or the like.

FIG. 7 is an enlarged cross-sectional view of the system 100 shown inFIG. 6. The sensor bonding layer 204 is disposed on a surface of anon-metallic wafer 702 of the sensor 104. The sensor 104 includes atleast one non-metallic wafer 702. In one or more embodiments, the sensor104 is a SAW device that is configured to sense one or more oftemperature data, strain data, or stress data of the structure 102. Forexample, referring back to FIG. 6, the sensor 104 may include a firstsensing element 610 that is elongated parallel to a longitudinal axis612 of the structure 102 and a second sensing element 614 that iselongated perpendicular to the first sensing element 610. The firstsensing element 610 may be configured to measure forces through thestructure 102 along the longitudinal axis 612, and the second sensingelement 614 may measure forces through the structure 102 perpendicularto the longitudinal axis 612. The one or more non-metallic wafers 702may be a single crystal quartz wafers that have piezoelectricproperties. The SAW device may be capped or sealed inside of a discretepackage. Optionally, the SAW device may be hermetically sealed.

The sensor bonding layer 204 is a metallic alloy that is disposed on(e.g., bonded to) a surface of the non-metallic wafer 702. The sensorbonding layer 204 can include or represent the materials of the sensorbonding layer 204 described above with reference to FIG. 2. Thestructure bonding layer 202 is a metallic alloy is disposed on (e.g.,bonded to) the outer surface 604 of the inlay 602, which is planar inthe illustrated embodiment. The structure bonding layer 202 can includeor represent the materials of the structure bonding layer 202 describedabove with reference to FIG. 2. The sensor bonding layer 204 is coupledto the structure bonding layer 202 via the metallic joint 106. Themetallic joint 106 can include a solder alloy as described above withreference to FIG. 2. The metallic joint 106 bonds to the sensor bondinglayer 204 and the structure bonding layer 202 to permanently affix thesensor 104 to the inlay 602 of the structure 102.

The inlay 602 in an embodiment is a different material than the materialof the structure 102 surrounding the inlay 602. For example, the inlay602 may include copper and the structure 102 may lack copper or mayinclude less copper by weight than the inlay 602. Some non-limitingexamples of suitable metals for the inlay 602 include copper, nickel,and platinum. These metals can be used individually as the inlay 602 orcombined with each other and/or other metals to provide an alloy withapplication-specific properties, such as stress resistance,solderability, and corrosion resistance. The inlay 602 in a non-limitingexample is copper or a copper alloy that includes more than 50% copperby weight. The structure bonding layer 202 can be tin or a tin alloythat is applied onto the copper inlay 602. The structure 102 could besteel, aluminum, or the like. In an alternative embodiment, the inlay602 has the same material composition as the structure 102 surroundingthe inlay 602. For example, the inlay 602 may be formed by milling thestructure 102 to remove material of the structure 102, thereby formingthe inlay 602 as an integral projection of the structure 102.

The inlay 602 is formed by depositing inlay material onto the structure102. For example, the inlay 602 can be formed in-situ on the structure102 via additive manufacturing, casting, or the like. Alternatively, theinlay 602 may be formed separate from the structure 102 and subsequentlybonded or otherwise mounted on the structure 102. For example, the inlay602 can be machined into a designated size and shape remote from thestructure 102, and subsequently brazed onto the structure 102 at a brazejoint. In an embodiment, the structure 102 defines a recess 704 alongthe surface 606. The inlay 602 is deposited into the recess 704. Theinlay 602 may fill the recess 704 and project out of the recess 704beyond the surface 606 of the structure 102. For example, the inlay 602may have a height or thickness greater than the depth of the recess 704such that the inlay 602 defines a pedestal projecting out of the recess704. Alternatively, the structure 102 does not define the recess 704,and the inlay 602 is deposited directly onto the surface 606 of thestructure 102.

In an embodiment, the inlay 602 can be designed to focus the straintransfer from the structure 102 to the sensor device 104 or to diffusethe high strain fields to the sensor device 104 to protect the sensor104 from cracking. The desired strain transfer and/or diffusioncharacteristics can be achieved by selecting the material properties ofthe inlay 602 and/or the geometric properties of the inlay 602. Thematerial of the inlay 602 can be selected based on the modulus propertyof the material. In a non-limiting example, the material of the inlay602 can include or represent a metal foam. Some metal foams have asubstantially low modulus of elasticity. The modulus of elasticity ofthe metal foam (e.g., 100 MpA or less) may even be lower than theorganic adhesive typically employed (e.g., at least 500 MpA). Utilizingthe metal foam in the inlay 602 can reduce surface strain to allow useof sensor in high strain environments without damaging the sensor. Thephysical shape, thickness (e.g., height), and/or outer surface sizeand/or shape of the inlay 602 can also affect the strain transfer.

The embodiment shown in FIGS. 6 and 7 can be formed using the method 300described with reference to FIG. 3. For example, prior to disposing thestructure bonding layer on the structure at 302, the method 300 caninclude depositing an inlay on the structure. The inlay can be copperand/or another metal. Then, the method 300 can include grinding theinlay such that an outer surface of the inlay is planar. After forming aplanar outer surface on the inlay, the method 300 proceeds to 302 andthe structure bonding layer is applied to the planar outer surface ofthe inlay. The structure bonding layer can include tin and/or anothermetal. The use of the inlay can enable the system to be used onnon-planar structures, such as cylindrical shafts, curved rotor blades,and the like, without compromising adhesion quality or sensing accuracy.

In one embodiment of the subject matter described herein, a systemincludes a structure bonding layer and a sensor. The structure bondinglayer is disposed on a structure. The structure bonding layer is ametallic alloy. The sensor includes a non-metallic wafer and a sensorbonding layer disposed on a surface of the non-metallic wafer. Thesensor bonding layer is a metallic alloy. The sensor bonding layer iscoupled to the structure bonding layer via a metallic joint, and thesensor is configured to sense data of the structure through the metallicjoint, the structure bonding layer, and the sensor bonding layer.

Optionally, the non-metallic wafer is single crystal quartz. Optionally,the structure bonding layer is one of electrolytic nickel gold orelectroless nickel immersion gold (eNIG). Optionally, the sensor is asurface acoustic wave (SAW) device, and the data of the structure thatis sensed by the sensor includes temperature data, stress data, and/orstrain data.

Optionally, the system also includes an inlay on the structure, and thestructure bonding layer is disposed on an outer surface of the inlay.The inlay is a different material than a material of the structuresurrounding the inlay. Optionally, the outer surface of the inlay isplanar, and a surface of the structure surrounding the inlay is curved.Optionally, the inlay is disposed in a recess defined within a surfaceof the structure. Optionally, the inlay projects beyond a surface of thestructure surrounding the inlay such that the outer surface of the inlayis offset relative to the surface of the structure. Optionally, theinlay includes copper. Optionally, the structure bonding layer includestin.

In an embodiment, a method includes disposing a structure bonding layeron a structure. The structure bonding layer is a metallic alloy. Themethod includes disposing a sensor bonding layer on a surface of anon-metallic wafer of a sensor. The sensor bonding layer is a metallicalloy. The method also includes coupling the structure bonding layer tothe sensor bonding layer via a metallic joint. The sensor is configuredto sense data of the structure through the metallic joint, the structurebonding layer, and the sensor bonding layer.

Optionally, the method further includes depositing an inlay on thestructure. The inlay is a different material than a material of thestructure surrounding the inlay, and the structure bonding layer isdisposed on an outer surface of the inlay. Optionally, the methodfurther includes grinding the inlay such that the outer surface of theinlay is planar prior to disposing the structure bonding layer on theouter surface. Optionally, the inlay includes copper, and the structurebonding layer includes tin. Optionally, the inlay is disposed in arecess defined within a surface of the structure. Optionally, the inlayis deposited to project beyond a surface of the structure surroundingthe inlay such that the outer surface of the inlay is offset relative tothe surface of the structure.

A system includes a sensor, an inlay, and a structure bonding layer. Thesensor includes a sensor bonding layer disposed on a surface of thesensor. The sensor bonding layer is a metallic alloy. The inlay isdisposed on a curved surface of a structure. The inlay includes a planarouter surface. The structure bonding layer is disposed on the planarouter surface of the inlay. The structure bonding layer is a metallicalloy. The sensor bonding layer is coupled to the structure bondinglayer via a metallic joint, and the sensor is configured to sense dataof the structure through the metallic joint, the structure bondinglayer, and the sensor bonding layer.

Optionally, the inlay projects beyond the curved surface of thestructure surrounding the inlay such that the outer surface of the inlayis offset relative to the curved surface of the structure. Optionally,the inlay is a different material than a material of the structuresurrounding the inlay. Optionally, the inlay includes a metal foam.Optionally, the sensor is a surface acoustic wave (SAW) device thatincludes a single crystal quartz wafer, and the surface of the sensor onwhich the sensor bonding layer is deposited is a surface of the singlecrystal quartz wafer.

In one embodiment of the subject matter described herein, a systemincludes a structure configured to have a structure bonding layerdisposed on a surface of the structure. The structure bonding layer is ametallic alloy. The system includes a sensor configured to have a sensorbonding layer disposed on a surface of the sensor. The sensor bondinglayer is a metallic alloy. The sensor bonding layer is configured to becoupled to the structure bonding layer via a metallic joint in order forthe sensor to sense data of the structure through the metallic joint,the structure bonding layer, and the sensor bonding layer.

Optionally, the sensor bonding layer is configured to be coupled to thestructure bonding layer via the metallic joint at a location outside ofa reflow oven. Optionally, the data of the structure includes one ormore of temperature data, stress data, or strain data. Optionally, thestructure is one or more of a shaft, a rod, or a blade. Optionally, thesensor is configured to self-align with the structure via the metallicjoint. Optionally, the structure bonding layer is configured to bedisposed on an outer surface of the structure.

Optionally, the system includes an induction coil configured to be inoperational contact with the metallic joint. The induction coil isconfigured to apply electrical stimuli to the metallic joint.

Optionally, the sensor is a surface acoustic wave (SAW) device.Optionally, the SAW device comprises one or more of a strain gauge, atorque sensor, or a temperature sensor.

In one embodiment of the subject matter described herein, a methodincludes disposing a structure bonding layer on a surface of astructure. The structure bonding layer is a metallic alloy. The methodincludes disposing a sensor bonding layer on a surface of a sensor. Thesensor bonding layer is a metallic alloy. The structure bonding layer iscoupled to the sensor bonding layer via a metallic joint in order forthe sensor to sense data of the structure through the metallic joint,the structure bonding layer, and the sensor bonding layer.

Optionally, coupling the sensor bonding layer to the structure bondinglayer via the metallic joint occurs at a location that is outside of areflow oven. Optionally, the data of the structure includes one or moreof temperature data, stress data, or strain data.

Optionally, the structure is one or more of a shaft, a rod, or a blade.Optionally, the sensor is configured to self-align with the structurevia the metallic joint. Optionally, the structure bonding layer isconfigured to be disposed on an outer surface of the structure.

Optionally, the method includes applying electrical stimuli to themetallic joint with an induction coil configured to be in operationcontact with the metallic joint. Optionally, the sensor is a surfaceacoustic wave (SAW) device. Optionally, the SAW device comprises one ormore of a strain gauge, a torque sensor, or a temperature sensor.

In one embodiment of the subject matter described herein, a systemincludes a structure configured to have a structure bonding layerdisposed on a surface of the structure. The structure bonding layer is ametallic alloy. The system includes a sensor configured to have a sensorbonding layer disposed on a surface of the sensor. The sensor bondinglayer is a metallic alloy. The sensor bonding layer is configured to becoupled to the structure bonding layer via a metallic joint at alocation outside of a reflow oven in order for the sensor to sense dataof the structure through the metallic joint, the structure bondinglayer, and the sensor bonding layer. Optionally, the sensor is a surfaceacoustic wave (SAW) device.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the presently describedinventive subject matter are not intended to be interpreted as excludingthe existence of additional embodiments that also incorporate therecited features. Moreover, unless explicitly stated to the contrary,embodiments “comprising,” “including,” or “having” (or like terms) anelement, which has a particular property or a plurality of elements witha particular property, may include additional such elements that do nothave the particular property.

As used herein, terms such as “system” or “controller” may includehardware and/or software that operate(s) to perform one or morefunctions. For example, a system or controller may include a computerprocessor or other logic-based device that performs operations based oninstructions stored on a tangible and non-transitory computer readablestorage medium, such as a computer memory. Alternatively, a system orcontroller may include a hard-wired device that performs operationsbased on hard-wired logic of the device. The systems and controllersshown in the figures may represent the hardware that operates based onsoftware or hardwired instructions, the software that directs hardwareto perform the operations, or a combination thereof.

As used herein, terms such as “operably connected,” “operativelyconnected,” “operably coupled,” “operatively coupled” and the likeindicate that two or more components are connected in a manner thatenables or allows at least one of the components to carry out adesignated function. For example, when two or more components areoperably connected, one or more connections (electrical and/or wirelessconnections) may exist that allow the components to communicate witheach other, that allow one component to control another component, thatallow each component to control the other component, and/or that enableat least one of the components to operate in a designated manner.

It is to be understood that the subject matter described herein is notlimited in its application to the details of construction and thearrangement of elements set forth in the description herein orillustrated in the drawings hereof. The subject matter described hereinis capable of other embodiments and of being practiced or of beingcarried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the presentlydescribed subject matter without departing from its scope. While thedimensions, types of materials and coatings described herein areintended to define the parameters of the disclosed subject matter, theyare by no means limiting and are exemplary embodiments. Many otherembodiments will be apparent to one of ordinary skill in the art uponreviewing the above description. The scope of the inventive subjectmatter should, therefore, be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled. In the appended claims, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Moreover, in the following claims, the terms“first,” “second,” and “third,” etc. are used merely as labels, and arenot intended to impose numerical requirements on their objects. Further,the limitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. § 112(f), unless and until such claim limitations expresslyuse the phrase “means for” followed by a statement of function void offurther structure.

This written description uses examples to disclose several embodimentsof the inventive subject matter, and also to enable one of ordinaryskill in the art to practice the embodiments of inventive subjectmatter, including making and using any devices or systems and performingany incorporated methods. The patentable scope of the inventive subjectmatter is defined by the claims, and may include other examples thatoccur to one of ordinary skill in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal languages of the claims.

What is claimed is:
 1. A system comprising: a structure bonding layerdisposed on a structure, wherein the structure bonding layer is ametallic alloy; and a sensor including a non-metallic wafer and a sensorbonding layer disposed on a surface of the non-metallic wafer, whereinthe sensor bonding layer is a metallic alloy; wherein the sensor bondinglayer is coupled to the structure bonding layer via a metallic joint,and the sensor is configured to sense data of the structure through themetallic joint, the structure bonding layer, and the sensor bondinglayer.
 2. The system of claim 1, wherein the non-metallic wafer issingle crystal quartz.
 3. The system of claim 1, further comprising aninlay on the structure and the structure bonding layer is disposed on anouter surface of the inlay, wherein the inlay is a different materialthan a material of the structure surrounding the inlay.
 4. The system ofclaim 3, wherein the outer surface of the inlay is planar and a surfaceof the structure surrounding the inlay is curved.
 5. The system of claim3, wherein the inlay is disposed in a recess defined within a surface ofthe structure.
 6. The system of claim 3, wherein the inlay projectsbeyond a surface of the structure surrounding the inlay such that theouter surface of the inlay is offset relative to the surface of thestructure.
 7. The system of claim 3, wherein the inlay includes copper.8. The system of claim 7, wherein the structure bonding layer includestin.
 9. The system of claim 1, wherein the structure bonding layer isone of electrolytic nickel gold or electroless nickel immersion gold(eNIG).
 10. The system of claim 1, wherein the sensor is a surfaceacoustic wave (SAW) device and the data of the structure that is sensedby the sensor includes one or more of temperature data, stress data, orstrain data.
 11. A method comprising: disposing a structure bondinglayer on a structure, wherein the structure bonding layer is a metallicalloy; and disposing a sensor bonding layer on a surface of anon-metallic wafer of a sensor, wherein the sensor bonding layer is ametallic alloy; coupling the structure bonding layer to the sensorbonding layer via a metallic joint, wherein the sensor is configured tosense data of the structure through the metallic joint, the structurebonding layer, and the sensor bonding layer.
 12. The method of claim 11,further comprising depositing an inlay on the structure, wherein theinlay is a different material than a material of the structuresurrounding the inlay and the structure bonding layer is disposed on anouter surface of the inlay.
 13. The method of claim 12, furthercomprising grinding the inlay such that the outer surface of the inlayis planar prior to disposing the structure bonding layer on the outersurface.
 14. The method of claim 12, wherein the inlay includes copperand the structure bonding layer includes tin.
 15. The method of claim12, wherein the inlay is disposed in a recess defined within a surfaceof the structure.
 16. The method of claim 12, wherein the inlay isdeposited to project beyond a surface of the structure surrounding theinlay such that the outer surface of the inlay is offset relative to thesurface of the structure.
 17. A system comprising: a sensor including asensor bonding layer disposed on a surface of the sensor, wherein thesensor bonding layer is a metallic alloy; an inlay disposed on a curvedsurface of a structure, the inlay including a planar outer surface; anda structure bonding layer disposed on the planar outer surface of theinlay, wherein the structure bonding layer is a metallic alloy, whereinthe sensor bonding layer is coupled to the structure bonding layer via ametallic joint, and the sensor is configured to sense data of thestructure through the metallic joint, the structure bonding layer, andthe sensor bonding layer.
 18. The system of claim 17, wherein the inlayprojects beyond the curved surface of the structure surrounding theinlay such that the outer surface of the inlay is offset relative to thecurved surface of the structure.
 19. The system of claim 17, wherein theinlay is a different material than a material of the structuresurrounding the inlay.
 20. The system of claim 19, wherein the inlayincludes a metal foam.
 21. The system of claim 17, wherein the sensor isa surface acoustic wave (SAW) device that includes a single crystalquartz wafer, and the surface of the sensor on which the sensor bondinglayer is deposited is a surface of the single crystal quartz wafer.